The present invention relates generally to airflow measuring assemblies. Particularly, the invention relates to powered capture hood assemblies to measure volumetric airflow. More particularly, the invention relates to a unitary powered capture hood assembly to measuring supply and return volumetric airflows in heating and cooling systems and ventilation fans, for example.
Heating, ventilating and air conditioning systems (HVAC) depend upon ductwork to deliver air from the air handler (typically part of the furnace or air conditioner) to individual rooms or spaces. Air delivery typically depends on duct sizing, construction and leakage and thus, measuring the air flow at each supply register and return air provides a means for the HVAC contractor to determine if the HVAC system is supplying proper airflow to a specified area and to the system. In residential HVAC systems, particularly due to the type and placement of the ductwork, accurate airflow measurements and balancing room to room flow as well as matching supply and return airflow help provide optimal comfort for the homeowner. However, because of the inherent ductwork construction, residential HVAC systems are difficult to measure by prior art devices.
Due to the increased desire for efficient heating, cooling and ventilation systems, it has become imperative that more accurate airflow measurement readings be achieved. Various measuring devices and assemblies have been used and proposed in the past to measure airflow in residential and commercial heating and cooling systems. However, these prior art devices have typically been passive devices and have been cumbersome and difficult to utilize in obtaining accurate airflow measurements. Other prior art devices have utilized flexible duct structures which required the on-site construction of flow boxes for use with a powered blower to measure airflow. The latter devices are difficult and time consuming to construct and utilize. The powered capture hood of the present invention overcomes the difficulties and limitations of prior art devices.
The powered capture hood of the invention provides the necessary flow conditioning and compensation for pressure loss to provide accurate airflow measurements. The powered flow capture assembly of the invention provides an easy to use assembly which yields accurate volumetric airflow measurements.